This is a repost of an earlier question I had, but I like to go into more details now to be able to fully solve this.

So again, with (normal) posts changing the permalink is as easy as going to Settings > Permalink and by changing it to anything you like such as the broadly used %category%/%postname%.html. This all works. If only this was as easy for the custom post type and it's taxonomies as well.

Then things will get tough, because we don't know by forehand how many subcategories there, maybe there are even none. So the structure we are after is portfolio/(CATEGORY PATH FROM TOP TO CHILD)/post.html. I am still stuck at this point. I think I should somehow get the last category added to the path and pass that along the project_category, which should lead to a taxonomy.php file where I can process it properly.

I haven't tackled this neither but it should have something to do with %postname%.html at the end of something.

I hope my problem is clear and that there are brave developers which will help me tackle this problem which has already keep me busy for four FULL days!